Pneumatic punch



26, 1969 R. GOLDMAN 3,463,042

' PNEUMATIC PUNCH Filed Nov. 25, 1966 IN VEN'IOR.

RUBIN GOLDMAN ATTORNEYS United States Patent US. Cl. 83-627 Claims ABSTRACT OF THE DISCLOSURE The punch assembly of this invention comprises a die, punch, and cylinder holder frame 10. A die 20 is mounted in the die holder. A sleeve 36 is mounted in the punch holder and aligned with the die, and a cylinder assembly 50 including a plunger 58 is mounted in the cylinder holder. A ball 28 is mounted in the lower end of and slidable axially in the sleeve 36, and a stem 38 is locked in the sleeve above the unch and is movable axially in the sleeve toward and away from the ball. Pneumatic actuating means, including an impulse valve 70, is connected to the cylinder assembly 50 for driving the plunger of the cylinder against the stem 38 causing the stem to drive the ball 28 against the die 20. A relatively heavy spring 42 is secured to the stem for returning the stem to its position away from the ball, and the spring 42 also assists in returning the plunger to its withdrawn position in the cylinder.

This application is a continuation-in-part of my copending United States application Ser. No. 409,415, filed Nov. 6, 1964, now Patent No. 3,299,761, dated Jan. 24, 1967.

The invention comprises a punch that includes a piercing means and detached stem biased away from the piercing means by relatively heavy spring means. The spring means serves not only to move the stem away from the piercing means but also pushes the actuating means away from the piercing means as well so as to relieve the piercing load instantaneously after it is applied so as not to interfere with the continuous movement of the stock.

FIG. 1 is a front elevation view, partly in cross section, showing one embodiment of the punch assembly constructed in accordance with this invention and showing the parts in their operative or punching positions;

FIG. 2 is a cross-sectional view similar to FIG. 1 showing the parts in their withdrawn or at rest positions; and

FIG. 3 is a cross-sectional view of a control valve forming part of the pneumatic control system for the assembly of this invention.

The punch assembly shown in FIGS. 1 and 2 includes a frame 10 having a die holder 12, a punch holder 14, and a cylinder assembly holder 16, aligned vertically with one another. The frame 10 may be an aluminum casting or some similar material having sufficient rigidity to withstand the shock to which such an assembly is normally subjected in use. The frame 10 also includes a clamp 18 in its rear portion so that it may be conveniently mounted on the machine handling the stock which is to be punched. Ordinarily, the punch is used as auxiliary equipment on a machine which performs the primary function of forming the article to be punched on the assembly. The punch assembly of this invention is particularly designed to punch holes in a continuously moving web of thin sheet material such as plastic film.

A die button 20 having its upper face 22 substantially in the plane of the upper surface 24 of the die holder 12 is in the form of a sleeve having a sharp upper inner edge 26 which cooperates with the ball 28 of the punch assemice bly to perform the cutting operation. The shape of the die button 20 is dictated by the shape of the hole to be punched and of course its cutting edge 26 must cooperate with the punch and be of a size which is compatable with it. The die button 20 rests upon an adjusting screw 30, and the screw 30 supports the button at the correct elevation in the holder. The adjusting screw enables the operator to periodically raise the die button 20 as wear occurs through continued use of the mechanism, and to compensate for regrinding of the upper surface of the button when it is sharpened at its cutting edge 26.

The punch assembly 32 mounted in the punch holder 14 includes a bushing 34 within which is seated a sleeve 36 fixed in the position shown. The sleeve 36 slidably carries the stem 38 of the punch as well as the ball 28, and the two are movable axially in the sleeve 36 relative to one another. Thus, the stem 38 may move axially in the sleeve 36 toward and away from the ball 28, and when the stem 38 is raised in the sleeve, the ball 28 which floats in position on the sheet drawn beneath it may move between the extremes established by the die button 20 as in FIG. 1 and the bottom 40 of the stem 38 as viewed in FIG. 2.

A heavy coil spring 42 surrounds the upper portion of the stem 38 and is captured in place between the flange 44 of sleeve 36 and the head 46 of the stem. The heavy spring 42 urges the stem 38 to the position shown in FIG. 2 wherein the lower end of the stem 38 lies approximately of an inch above the ball 28. As is explained in detail below, to form a hole, the stem 38 is driven, against the action of the spring 42, downwardly against the ball 28 to cause the ball to strike at the cutting edge 26 of the die button so as to cut a circular hole in the stock which lies between the ball 28 and the button.

The cylinder assembly 50 mounted on the cylinder holder 16 includes a body 52 having a downwardly extending externally threaded collar 54 which extends through a hole in the holder 16 and a nut 56 threaded on the lower portion of the collar which holds the cylinder assembly in place. Cylinder plunger 58 extends out of the collar 54 below the nut 56 and serves as the direct actuator for the punch assembly 32. The cylinder assembly 50 is pneumatically actuated by a control system which is described in detail below.

Holder 16 for the cylinder assembly is adjustably mounted on the frame 10 as is shown in FIG. 1. The holder 16 is a separate casting which is slidably mounted on the vertical leg 60 of the frame 10 and is held in place by the bolt and nut 62 that extends through an enlarged hole in the vertical leg 60. A set screw 64 screwed into the top vertical leg 60 of the frame, engages the side of the screw 62 and serves as a stop to prevent it (and thus the holder 16) from riding upwardly in the slot and on the leg. Thus, the location of the cylinder 52 with respect to the punch unit 32 may be precisely adjusted.

The cylinder assembly 50 is so mounted on the frame 10 that the plunger 58 lies at the very bottom of its stroke when it engages the head 46 of the stem 38 which in turn is in its lowermost position wherein it engages the ball 28 which in turn is in the cutting position on the button 20. That is, the plunger in the position shown in FIG. 1 is fully extended in the operative position. In FIG. 2, the plunger is shown in the fully withdrawn position or the rest position between strokes.

The cylinder 52 in FIG. 1 carries an impulse valve 70 which is shown in detail in FIG. 3. The impulse valve has a control inlet 72 and an operative inlet 74. The inlet 72 is connected by flexible tubing 76 (shown schematically in FIG. 1) to the outlet of a solenoid valve 78, while the operative inlet 74 is connected by flexible tube 77 (shown schematically) to a constant supply of compressed air. The supply is represented by the arrow 80 on the left side of the pressure gauge and indicator assembly 82.

The impulse valve 70 shown in FIG. 3 in detail includes the operative inlet fitting 74 adapted to be connected to the compressed air source and an outlet 90 which in FIG. 1 is shown secured to the top of the cylinder 52. Flow from the inlet 74 is through passage 92 in the body of the valve and an opening 94 in a rubber diaphragm 96 to chamber 98. When the rubber diaphragm moves to the right as shown in FIG. 3 it forms a gap between its conical portion 100 and the valve seat 102, and air may flow directly from the passage 92 into the axial passage 104 in the body which in turn communicates with the outlet 90. The control inlet 72 is also adapted to be secured to a compressed air source as shown in FIG. 1. When so connected, air under pressure is directed against the left face of a second diaphragm 108 mounted on the left end of passage 104. The diaphragm 108 is mounted in tandem with the diaphragm 96 by means of the pin connection 110, and when the pressure exerted against the left face of the diaphragm 108 exceeds the pressure exerted against the right face of the diaphragm 96 from chamber 98, the conical portion 100 of diaphragm 96 moves from the seat 102 and the inlet and outlet 74 and 90 respectively, are placed in communication with one another. Thus, it is seen that compressed air may be directed through the impulse valve 70 to activate the cylinder 52 to drive the plunger 58 downwardly when the control inlet 72 is connected to a compressed air source. The impulse valve 70 may be closed by spring 112 within the impulse valve body which causes the conical portion 100 of the diaphragm 96 to seat against the valve seat 102. Thus, the spring 112 prevents additional compressed air from being delivered through the impulse valve when the pressure is relieved at the control inlet 72.

The punch assembly described above is designed to punch holes in continuously moving stock that is fed over the surface 24 of the die holder 12. When the machine is at rest and stock S is being drawn over the surface 24, the ball 28 forming part of the punch floats in the sleeve 36 on the surface of the stock, and its travel is limited only by the bottom 40 of the stem 38 and the stock itself. The heavy duty spring 42 supports the stem with the stem bottom about /a of an inch above the top of the ball. The cylinder assembly is positioned by means of the adjustment of its holder 16 so that the plunger 58 is in the fully extended position or at the bottom of its stroke when ball 28 is in the cutting position, and stem 38 is against the ball with the head 46 of the stem engaged by the bottom of the plunger. The relatively heavy spring 42 drives the stem 38 upwardly and the stem consequently pushes the plunger upwardly to assist in its return immediately as the plunger reaches its lowest position. The blow of the plunger against the stem 38 causes the ball 28 to pierce a perfect hole in the moving stock, and the frequency of operation of the device may be controlled by the solenoid 78. The cutting load applied by the cylinder to the ball is almost instantaneous, and the spring 42 relieves the load the moment it is applied. Thus, the piercing operation does not interfere with the continuous movement of the stock through the machine.

In operation, the inlet 80 is connected to a compressed air source, and the duct 77 constantly applies pressure to the inlet 74 of the impulse valve. The solenoid 78 is connected to an energizing circuit which may include a timer that cycles the solenoid at a frequency determined by the speed of movement of the stock and the desired spacing between holes to be formed in the stock by the punch. Each time the solenoid 78 opens, pressure is applied through inlet 72 in the impulse valve against diaphragm 108. When pressure is applied to diaphragm 108 to open the impulse valve, the constantly available compressed air at the inlet 74 passes through the impulse valve to the cylinder 52 to drive the plunger downwardly against the stem 38. When the solenoid 78 completes its cycle by 4 once again closing, the pressure is relieved from the left side of the diaphragm 108 in the impulse valve and the plunger is allowed to return under the influence of the heavy duty spring 42 and the spring (not shown) in the cylinder 52. The pressure in the tubing 76 may be vented by the solenoid in the conventional manner.

From the foregoing description those skilled in the art will appreciate that numerous modifications may be made without departing from the spirit of the invention. Therefore, it is not intended to limit the scope of this invention to the single embodiment illustrated and described. Rather, it is intended that the invention be limited only by the appended claims and their equivalents.

What is claimed is:

1. A punch assembly comprising:

punch, die and cylinder holders,

a die mounted in the die holder,

a sleeve mounted in the punch holder and aligned with the die,

piercing means mounted in the lower end of and slidable axially in the sleeve,

a stem mounted in the sleeve above the piercing means and movable axially in the sleeve toward and away from the piercing means,

a cylinder assembly including a plunger having a drive and return stroke mounted in the cylinder holder with the plunger aligned with the stem,

pneumatic actuating means connected to the cylinder assembly for driving the plunger against the stern causing the stem to drive the piercing means against the die,

and a relatively heavy coil spring surrounding the upper portion of the stem and bearing against the sleeve for rapidly relieving the load on the piercing means at the end of the drive stroke of the plunger.

2. A punch assembly comprising:

punch, die and cylinder holders,

a die mounted in the die holder,

a sleeve mounted in the punch holder and aligned with the die,

piercing means mounted in the lower end of and slidable axially in the sleeve,

a stem mounted in the sleeve above the piercing means and movable axially in the sleeve toward and away from the piercing means,

a cylinder assembly including a plunger having a drive and return stroke mounted in the cylinder holder with the plunger aligned with the stem,

pneumatic actuating means connected to the cylinder assembly for driving the plunger against the stem causing the stem to drive the piercing means against the die,

and spring means secured to the stern for returning the stem to a position away from the piercing means and causing the stem to push the plunger in its return stroke away from the sleeve,

the plunger being at the end of its drive stroke when the plunger engages the stem which in turn engages the piercing means which in turn is in cutting position against the die.

3. A punch assembly as defined in claim 2 further characterized by:

said spring means comprising a relatively heavy coil spring surrounding the upper portion of the stem and bearing against the sleeve for rapidly relieving the load on the piercing means at the end of the drive stroke of the plunger.

4. A punch assembly as defined in claim 1 further characterized by:

said pneumatic means including an impulse valve having an actuating inlet and control inlet connected between the cylinder and a source of compressed alr,

means for applying a constant source of compressed air to the actuating inlet,

and means for cyclically applying pressure to the control inlet to open the impulse valve so as to connect the actuating inlet to the cylinder. 5. A punch assembly as defined in claim 2 further characterized by:

the piercing means being a ball. 6. A punch assembly as defined in claim 2 further characterized by:

means for adjusting the position of the cylinder relative to the stem. 7. A punch assembly comprising: a frame, piercing means mounted for sliding movement in the frame, a stem slidable relative to the piercing means for moving the piercing means to its stock piercing position, drive means including a cylinder and plunger with the plunger engaging the stem and being at its fully extended position as the piercing means reaches its piercing position, and spring means secured to the stem for moving the stem away from the piercing means and pushing the drive means to an inoperative position. 8. A punch assembly as defined in claim 1 further characterized by:

the piercing means being a ball. 9. A punch assembly comprising: punch, die and cylinder holders, a die mounted in the die holder, piercing means mounted on the punch holder and aligned with the die,

a stem mounted on the punch holder and moveable axially toward and away from the die for driving the piercing means against the die,

a cylinder assembly including a plunger having a drive and return stroke mounted on the cylinder holder with the plunger aligned with the stem,

pneumatic actuating means connected to the cylinder assembly for driving the plunger against the stem causing the stem to drive the piercing means against the die,

and a relatively heavy coil spring surrounding the stem for rapidly relieving the load of the piercing means against the die by moving the stem away from the die.

10. A punch assembly as defined in claim 9 further characterized by:

means for adjusting the position of the cylinder relative to the stem.

References Cited UNITED STATES PATENTS 2,980,320 4/1961 Lapointe 234-4-1 3,096,015 7/1963 Bradbury 234107 3,283,974 11/1966- DeBoo 234-131 3,299,761 1/ 1967 Goldman 234-407 X WILLIAM S. LAWSON, Primary Examiner US. Cl. X.R. 

